Great game and gameplay loop. Switching the characters was a really cool mechanic. I first played it without the cayote time, and it definitely feels better with it (although the time may be a bit too long? at least from a visual perspective it can look be quite far off the stage while still able to jumping).
One cool thing to explore would be if you're able to push the other characters during the time
One thing I think would really help is if your fallen comrades don't disappear (so you can go past their dead bodies when you redo the level with the new person). Could also have some blood splatters left on the level.
Landing & jumping effects would also add a lot with how much they're a focus
I think an ability to look ahead and plan out how you're going to tackle the level would be cool
I would often do a sequence for one of the characters, and then swap to the wrong character, accidentally move, and then having to repeat that sequence a couple of times. Some undo function might be nice? Or in general optional saving after doing one of the characters? But could make it too easy, not sure. (These things were more stuff I noticed with the more difficult levels)
Overall really enjoyed the gameplay and had a great time playing it.